Question: $ { \left[\begin{array}{rr}{1} & {-1} \\ {1} & {0} \\ {2} & {-2}\end{array}\right]-\left[\begin{array}{rr}{3} & {1} \\ {3} & {0} \\ {4} & {1}\end{array}\right] = {?} } $
Answer: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{1}-{3} & {-1}-{1} \\ {1}-{3} & {0}-{0} \\ {2}-{4} & {-2}-{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-2} & {-2} \\ {-2} & {0} \\ {-2} & {-3}\end{array}\right]}$